[Docs] Fix malformed markdown link to Generative AI curriculum

[GziXnine]

Description

Fixes a malformed markdown link in the main README that prevents users from clicking through to the Generative AI for JavaScript course. This was a copy-paste error that introduced an extra [ character in the markdown link syntax.

The Bug

The link had an extra opening bracket [ before https, breaking the markdown link functionality:

Before (broken):
Visit https://aka.ms/genai-js-course to get started!

After (fixed):
Visit https://aka.ms/genai-js-course to get started!

This fix ensures that users can successfully click the link to access the Generative AI curriculum.

Fixes #1677

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Notes

• Files changed: 1 (README.md)
• Lines changed: 1
• Impact: Low risk, high value user experience improvement
• Branch: docs/fix-genai-js-link